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"Code 28" Error Message About ACPI-Compliant Embedded Controller Appears on IBM ThinkPad

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This article was previously published under Q286717
SYMPTOMS
After you install Windows XP on an IBM ThinkPad portable computer (model A20M, A21M, or X20), Device Manager displays the following error message, which is marked with a yellow icon:
UNKNOWN DEVICE
Code 28 -- No drivers are installed for this device. The location of the device is listed on LOCATION: on Microsoft ACPI-Compliant Embedded Controller.
CAUSE
This behavior occurs because Windows XP has no built-in Advanced Configuration and Power Interface (ACPI) driver for the embedded ACPI controller that comes with these models of the IBM ThinkPad portable computer.
RESOLUTION
To resolve this behavior, contact IBM to obtain an updated driver for the embedded ACPI controller.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
MORE INFORMATION
The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

For more information about hardware and software vendor contact information, visit the following Microsoft Web site: For more information about ACPI, review the following Microsoft Knowledge Base articles:
244806 Overview of Power Management in Windows 2000
242495 Troubleshooting Advanced Power Management in Windows 2000
Properties

Article ID: 286717 - Last Review: 10/18/2001 08:47:00 - Revision: 1.3

  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
  • kb3rdparty kbenv kberrmsg kbhardware kbprb KB286717
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